This episode explores the Mongols' surprising and largely forgotten naval ambitions. We look at how a steppe empire tried to build fleets and use sea power, from the early conquest of the Jin dynasty when they learned naval warfare from Song defectors, to Khubilai Khan's massive armadas against Japan, Vietnam, and Java. We dive into the practical challenges: logistics, shipbuilding, foreign crews, and storms. And we ask why the Mongols, who conquered more land than anyone else, ultimately failed at sea. Along the way we meet figures like the Chinese admiral Guo Kan, who served the Mongols, and we discuss the Battle of Bạch Đằng in 1288, where Đại Việt's Trần Hưng Đạo used stakes and the tide to destroy a Yuan fleet. We also consider the role of the Yam and the Silk Road in moving goods over land, making sea routes less pressing. This is a story of ambition, innovation, and the limits of empire.